Linear actuators that utilize a voice coil motor to highly responsively move and focus a lens, among other actions, are widely used. In the linear actuator disclosed in Patent Document 1, the center of a linear guide for guiding a movable element that performs a linear reciprocating motion is aligned with the center of gravity of the movable element, whereby durability and precision of positioning are improved.
The linear actuator disclosed in Patent Document 1 has a coil, and a coil assembly comprising a rectangular coil frame for supporting the coil. A linear guide, a frame for attaching a lens, a sensor for detecting the position of the movable element, and other members are disposed inside the coil frame.